1. Field of the Invention
The present invention relates to a volume hologram laminate which can reduce spotty hologram flaws produced by stacking or by storage under pressure during transport or warehousing, and to a label for fabrication of a volume hologram laminate.
2. Description of the Related Art
Volume hologram laminates developed in the past have generally had a construction wherein an adhesive layer, a volume hologram layer, an adhesive layer and a transparent protective film are laminated in that order on a substrate, the substrate for the adhesion being of various forms such as examination admission tickets, ID cards, small booklets such as passports and so forth; however, in the case of dry volume phase-type hologram recording materials wherein the hologram recording material is a recording material comprising a matrix polymer and a photopolymerizable compound, a problem is presented by spotty hologram flaws which occur during stacking for transport or warehousing or storage under a state of pressure, as in the case of books, for example.
Such spotty hologram flaws become apparent by observing the hologram recording layer, and the spots are oval-shaped with a long axis of 0.2-2 mm and a short axis of 0.1-1.5 mm, approximately, or circular with a radius of about 0.1-2 mm, occurring in a regular arrangement. Because this type of hologram flaw depends on the light source and the angle from which it is viewed, it can be considered a holographic flaw instead of contamination by air bubbles or foreign matter in the volume hologram layer.
It is an object of the present invention to provide a volume hologram laminate free of such hologram flaws and a label for fabrication of the volume hologram laminate, and it is a further object to provide a volume hologram laminate with low occurrence of spotty hologram flaws in the volume hologram layer even when kept under a state of pressure during storage, etc., as well as a label for fabrication of the volume hologram laminate.